Poor accelleration S320

You have to better describe what the car does and doesn't do for anyone to give you a meaningful suggestion.

Sorry,

When you "kickdown", the rate of acceleration is constant, although slow. I remember when I used to put my foot down, the rate of increase pushed you back into your seat.

Thanks again

Sounds like you got tranny trouble.

If the transmission's shifts are appropriate to the driver's demands the problem arises from insufficient air or fuel into the motor, turbocharger failure or possibly a blocked (or pinched shut) exhaust line. Also, don't exclude bad fuel or gasoline in the fuel.

A dirty air or fuel filter would show itself to be so on acceleration and long hill climbs both of which require lots of air and fuel.

Generally, diesels' fuel injection systems are designed for constant speed use so a means to add fuel for brisk acceleration is needed for automotive applications. In older M-B diesels this is done by monitoring the turbocharger's boost pressure and adding fuel as the boost pressure rises. Such system's malfunction can be caused by no turbo boost, sensor failure, a blocked or broken plastic transmission line etc.. Your modern diesel is more complex and have issues beyond those described here.

If the car was driven over curb or stone the exhaust pipe could have been crushed shut, choking the motor.

Those are what generally comes to mind, hope it helps find the cause.

Thanks for the replies guys.